1. Field of the Invention
This invention relates to a cap for writing instruments such as a mechanical pencil, a ball-point pen, and the like, and particularly to a cap for writing instruments to which a safety measure is applied so that even if a curious infant should inadvertently swallow a cap, which as a result becomes lodged in his (or her) throat, ventilation of air is secured.
2. Description of Background Information
The cap for writing instruments to which a safety measure is provided has been hitherto known in the technical field concerned. In general, a cap is designed for the purpose of protecting the writing instrument from a physical damage or for the purpose of improving a design (such as an ornamentation), the cap being detachably mounted on an extreme end (a pen-point) or a rear end of writing instruments. For example, in a case of a cap for a mechanical pencil, a so-called knock-cap, the cap is designed to protect an eraser mounted at a rear end of a tube in which a lead container (a refill) is provided, whereby when an eraser is used or when an eraser is removed and a mechanical lead is placed in the lead container, it can be removed in a simple operation, such as by pulling it off.
Caps for writing instruments to which a safety measure is provided as described above are disclosed, for example, in Japanese utility Model Laid-Open Nos. HEI 4-77489, 4-104485, 4-104486 Publications, and various ventilating constructions have been known.
Any of the conventional caps described above are safety caps which can provide passage of air by the presence of a ventilation construction such as a vent hole provided in the cap itself even if an infant or the like should inadvertently swallow the cap. However, as a result the external (contour) shape is impaired, and the design is adversely affected. For example, in the case of the caps disclosed in Japanese utility Model Laid-Open Nos. HEI 4-104485 and 4-104486 Publications, radially extending ribs are provided which extend outwardly from a tubular portion and toward a rear end of the cap from a centrally located shoulder of the cap and in an axial direction. A vent hole is provided in the end of the tubular member, and the cap has an external shape with a cylindrical body and spherical end shape peculiar to the cap. Accordingly, an object of the present invention is to prevent the degrading of a design or ornamentation for the article while providing a safety measure so that even if a curious infant should inadvertently swallow a cap, which as a result becomes lodged in his (or her) throat, passage of air is maintained.
Further, another object of the invention is to further improve a design of the goods in which a ventilating construction of the safety measure appears to form a pattern.